Switch apparatus

ABSTRACT

A simple solution to a longstanding, vexing problem of telephone switches is disclosed. By flexing a smooth, flat member between spaced-apart points on a switch frame, the member bows into a fender that prevents rubbing and chafing of movable wires within such frame. Attendantly, crosstalk and maintenance problems are (virtually) eliminated.

United States Patent Bowers Feb. 8, 1972 [54] SWITCH APPARATUS [72] Inventor: Daniel G. Bowers, Rochester, NY.

[73] Assignee: Eastman Kodak Company, Rochester,

[22] Filed: Dec. 16, 1970 [21] Appl. No.: 98,809

[52] U.S.Cl. ....200/166 A, 174/136 [51] Int. Cl. ..H0lh 9/00 [58] Field ofSearch .,.....335/l08,109,110,111;

174/136; 200/176, 166 L, 19 WG,166 A [56] References Cited UNITED STATES PATENTS 3,249,679 5/1966 Bogese .....174/136 x 3,251,161 5/1966 Stim ..l74/l36X 1,884,910 10/1932 Strowger ....335/1 11 2,844,656 7/1958 Lohs ..335/l09 Primary Examiner-H. 0. Jones Attorney-Walter O. Hodsdon and Robert F. Cody [5 7] ABSTRACT A simple solution to a longstanding, vexing problem of telephone switches is disclosed. By flexing a smooth, flat member between spaced-apart points on a switch frame, the member bows into a fender that prevents rubbing and chafing of movable wires within such frame. Attendantly, crosstalk and maintenance problems are (virtually) eliminated.

4 Claims, 4 Drawing Figures mcminm 8 m2 3.641.297

SHEET1UF4 V I0 I2 f 5 .7 J \H J FIG! DANIEL G. BOWERS PRIOR ART MENTOR ATTORNEY PATENYEDFEB a ma SHEET 2 OF 4 PRIOR ART DANIEL G. BOWERS INVENTOR.

J I ATTORNEY PATENTEDFEB a ma SHEET 3 OF 4 FIG. 3,

DANIEL G. BOWERS INVENTOR.

QM M- Z ATTORNEY PAIENTED 8 I972 SHEET 4 [IF 4 FIG. 4

DANIEL G BOWERS INVENTOR.

ATTORNEY SWITCH APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to electrical switches and in particular to switches having contact wiper assemblies which may move either, or both, along or about the same axis.

2. Description Relative to the Prior Art Electrical switches having contact wiper assemblies which may move up and down, and which may rotate as well, have been used in various applications requiring many interconnections in a relatively small space. A common use for switches of this type is in a telephone system, where banks of switches interconnect a multitude of telephone lines. US. Pat. No. 1,884,910, issued on Oct. 25, 1932, indicates a (general) kind of switch, which, as modernized, serves as the workhouse of many telephone switching systems.

In any switch having a contact wiper assembly which is free to move along or about an axis, a critical component thereof is the wire or wire bundle used to connect such wiper assembly with the external terminals of the switch. Such wire or wire bundle must necessarily be flexible; and especially in the case of a wire bundle, the wires must be insulated from each other, from the metal frame, and preferably made up of multistranded, small gauge wires. The wire bundle must be free to move and to flex to permit movement of the wiper assembly. During such combined movement and flexing, the bundle frequently comes in contact with, and abrades against, various parts of the switch frame, the usual application of such switch involving frequent and repeated actuations. Constant abrasion eventually causes the insulation on the switch wires to wear through, exposing bare wires which may then make electrical contact with each other and/or with the switch frame, producing incorrect connections and undesired crosstalk among telephone lines. Increasing the thickness of the insulation or otherwise armoring the cable is not practical, since such techniques tend to inhibit the freedom of motion of the wiper assembly.

Though the switch in question has been in use in telephone applications for many years, the problem of frayed and worn wiper assembly wires, and their replacement, has been tolerated as an inherent maintenance situation. The replacement of worn and defective wire bundles is a costly operation requiring a large stock of replacement parts and many manhours of skilled labor to effect the replacements.

SUMMARY OF THE INVENTION To eliminate the longstanding problemwith switches of the indicated type-of either replacing wire bundles after a short circuit is detected or implementing an expensive preventative maintenance program, the invention provides a bumper or fender which causes the wire bundle to glide across, rather than abrade against, the lower portion of the switch frame. The bumper or fender is smooth, and so arcuately shaped, that the actual surface contact between the wire bundle and the fender is minimal. The fender is of such configuration that two related but independent functions are provided by a unitary element.

OBJECT OF THE INVENTION To provide greater assurance against crosstalk in switches of the indicated type, and to minimize maintenance procedures therefor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a prior art telephone line finder switch which is improvable by means of the invention,

FIG. 2 is a partial view illustrating such switch in an actuated or switching position,

FIG. 3 is an "actuated view of the switch of FIGS. 1 and 2 improved by means of the invention, and

FIG. 4 is an at-rest view of the switch of FIG. 3.

With reference to FIG. 1, a switchactuating mechanism 4 is adapted to raise a central shaft 5 vertically until a vertical wiper 6 makes electrical contact with a switching point on a vertical contact bank 7. The actuating mechanism 4 then rotates the central shaft 5 until the line wipers 8, 9, and 10 contact selected points. Each time the central shaft 5 rotates or moves up or down, the wire bundle 11 twists and flexes to accommodate such motion; such twisting and flexing occurs because the wire bundle 11 is attached to the line wipers by cord holders l2 and 13. The wire bundle 11 is secured to the switch frame by a cord holder 14.

When the switch is at rest, awaiting actuation, as in FIG. 1, the wire bundle ll rests against a lower bank rod 16 and a lower bank plate 17. As the switch actuates to position the wipers to make switching connections, the wire bundle 11 brushes against the lower bank rod 16 and the lower bank plate 17, after which the bundle 11 gets suspended within the inside of the switch between cord holders l2 and 14. See FIG. 2, which shows the wire bundle ll twisted over, and raised up and out of contact with the switch body.

To avoid the prior art problems of crosstalk and costly maintenance caused by repeated contact between the wire bundle 11 on the one hand and the lower bank rod 16 and lower bank plate 17 on the other, the invention proposes the use of a fender 21 to hold the wire bundle 11 away from the switch rod 16 and plate 17. See FIGS. 3 and 4. The fender 21 comprises a smooth, flat strip of electrical insulating material. One end of the fender 21 is provided with a slot 40 for securing the fender 21 to the frame of the switch by means of an existing screw 20 that secures the vertical contact bank 7 to the switch frame; and the other end of the fender 21 is provided with a notch 42 that cradles the bank rod 16, the lower bank plate 17 causing the fender 21 to bow out and away from the bank rod 16. It is to be noted that because the vertical contact bank 7 and the screw 20 are forward of the switch frame, the fender 21when fastened by the screw 20 to the bank 7 and butted against the lower bank rod l6is provided with both straight and arcuate portions, the former providing large-area support for holding the wire bundle 11 away from the switch frame when the wipers are in their up" positions, and the latter presenting a camming surface for guiding the wire bundle away from the switch frame when the wipers move from their down" positions.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. For example, rather than add a bladelike fender to the switch of FIGS. 1 and 2, the lower portion of the switch frame could be preformed in the requisite shape to accomplish the desired effect.

What is claimed is:

I. In an electrical switch of the type having:

a. a wiper assembly movable along and about an axis,

b. at least one terminal for an external electrical connection,

c. at least one wire electrically connecting the wiper assembly to the external terminal,

d. means for moving the wiper assembly along and about its said axis, e. a bank rod, and f. a bank plate connected to said bank rod and residing in a plane substantially perpendicular to the said bank rod, said bank plate having an arcuately shaped edge proximate the interior of the said switch, the improvement wherein:

the bank rod is provided with a fender surface at the end thereof which is proximate the bank plate, said surface residing between said bank rod and said bank plate on the one hand and the said wiper wire on the other.

2. The improvement of claim 1 wherein the said fender is inthe form of an elongated, thin, leaflike member.

3. The improvement of claim 1 wherein the said fender is electrically nonconductive and wherein the surface of said fender which is proximate said wiper wire is smooth.

4. The improvement of claim I,

said slotted end embracing said bosslike means, and said notched end embracing said bank rod proximate said bank plate, thereby to cause said fender to present a straight portion near the said bosslike means and a curved portion near the connection of said bank rod and said bank plate. 

1. In an electrical switch of the type having: a. a wiper assembly movable along and about an axis, b. at least one terminal for an external electrical connection, c. at least one wire electrically connecting the wiper assembly to the external terminal, d. means for moving the wiper assembly along and about its said axis, e. a bank rod, and f. a bank plate connected to said bank rod and residing in a plane substantially perpendicular to the said bank rod, said bank plate having an arcuately shaped edge proximate the interior of the said switch, the improvement wherein: the bank rod is provided with a fender surface at the end thereof which is proximate the bank plate, said surface residing between said bank rod and said bank plate on the one hand and the said wiper wire on the other.
 2. The improvement of claim 1 wherein the said fender is in the form of an elongated, thin, leaflike member.
 3. The improvement of claim 1 wherein the said fender is electrically nonconductive and wherein the surface of said fender which is proximate said wiper wire is smooth.
 4. The improvement of claim 1, a. wherein the said fender is formed with a slot at one end and with a notch at the other end, b. wherein said bank rod has bosslike means protruding from said bank rod toward the interior of said switch, and c. wherein the distance between said bosslike means and the connection of said bank rod and said bank plate is less than the length of the said fender, said slotted end embracing said bosslike means, and said notched end embracing said bank rod proximate said bank plate, thereby to cause said fender to present a straight portion near the said bosslike means and a curved portion near the connection of said bank rod and said bank plate. 